The present invention relates to an electrical connection box used for wiring a car or the like and a method of producing the electrical connection box.
An electrical connection box of this kind generally has a structure in which circuits including a number of branch connection portions of a wire harness are incorporated and a number of relays and fuses are provided collectively.
FIG. 8 shows an example of an electrical connection box, in which wiring-plate assemblies a, b, c ... each having an insulating plate 3 and a plurality of bus bars 4 are laminated in order and housed within a main casing 1 and a lower casing 2. Tab terminals 5 which branch from each of the bus bars 4 and project upward or downward are inserted into connection portions such as connector housings 9, fuse cavities 10, or the like, through holes 6 formed in the insulating plates 3, and are connected to a terminal connector 9 of a wire harness W, blade-type fuses 11, relays 12, circuit breakers 13, and the like. Relay terminals 8, each having female terminal portions 7 at its opposite ends, are interposed between the fuses 11, etc. and tab terminals 5, if necessary.
As shown in FIG. 9, conventionally, an electrical connection box A, as described above, is provided on a cowl side C in the vicinity of a meter board M of an instrument panel P. As shown FIGS. 10 and 7b, the electrical connection box A is connected to an engine-side harness We, a panel-side harness Wp a cowl side harness Wc etc., through the connector housing 9, and further connected to an ignition switch SW 14, a group of meters 15, switches 16 and accessories 17 such as a radio or a cigar lighter on the instrument panel P through a plurality of sub-harnesses Ws.
The space for mounting this conventional electrical connection box A is limited to the cowl side, and the internal circuit of the electrical connection box A has a structure of lamination of the wiring-plate assemblies a, b, ... (FIG. 8). Accordingly, various problems occur as follows.
(1) The mounting space at the cowl side portion is too small to sufficiently provide the capacity for housing the electrical connection box, and it is therefore impossible to house necessary joints (branch connections), relays, fuses, etc. PA0 (2) Accordingly, the number of joints between electrical wires is increased, so that the electrical connection box becomes large. PA0 (3) The electrical connection box attaching position is a separated distance from objects to be connected such as the ignition switch SW 14, the meters 15, etc., as shown in FIG. 7b so that the number of the going and returning circuits (sub-harnesses Ws) is too large to thereby make the wire harness. resulting in a complicated configuration. PA0 (4) If the internal structure of the electrical connection box is partially changed depending on the kind, grade, or the like of a car, it becomes necessary to produce the entire electrical connection box again so that the cost rises.